1. Technical Field
The present invention relates to ventilation systems for masks, and more particularly to new and improved active/passive ventilation systems and methods for the goggles of a face mask.
2. Background Art
Fog formation on the eye-protecting goggles of face masks has long been a problem. The major difficulty is the limited ventilation in the small space that protects and surrounds the eye area of the wearer. Solutions typically fall into three areas: improving ventilation, heating the transparent screen (window), or coating the screen with water-repellant materials. Some of these solutions have been “passive”, in the sense that they try to prevent fogging of the goggles without requiring external power or affirmative action by the wearer. Some have been “active”, in the sense that they require the wearer to do something to remove or prevent fogging. Some have been “powered”, in the sense that they require external power sources, such as batteries, to function.
Unfortunately, there is still a need to improve such mask defogging designs. For example, powered systems can be uncomfortably heavy. Power sources must be maintained and replenished. In addition, powered systems can be loud, preventing good hearing.
Where vigorous activities are involved, such as heavy labor or competitive sports, passive ventilation systems and anti-fog coatings can be overwhelmed by increased breathing rates, body heat, and perspiration. Furthermore, anti-fog coatings can degrade, especially after repeated washing and cleaning. Increased respiration in such cases is also incompatible with “active” ventilation systems since defogging the mask requires action by the wearer. Such action distracts or impedes the wearer at the very times that the mask should be truly free breathing (i.e., having no impediments that restrict or interfere with the wearer's breathing).
What is needed is a highly effective defogging system that operates totally passively. For competitive sports, it is particularly important that defogging the mask operates totally passively so as not to distract the wearer or interfere with speech in any way. During activities such as skiing and laboratory research, the wearer must also not be distracted with fogged masks.
What is also needed is a way to positively purge the goggle area, with no reverse air flow back into the goggle area. This is important during heavy respiration, so that portions of the wearer's humid breath are not reintroduced into the goggle area.
Furthermore, what is needed is a way for the wearer to deliberately increase ventilation in the goggle area. It must be recognized that a passive system, no matter how effective, may be used under such extreme circumstances that additional assistance from the wearer could be needed. The wearer should be able to defog the mask by deliberately forcing increased ventilation into the mask goggle area when desired.
Finally, what is needed is a way to retrofit masks that have already been fabricated with an improved defogging system. Many people, such as paintball players and motorcycle riders, have already invested in very expensive masks and helmets. Retrofitting their current masks would be highly favorable to purchasing entire new systems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.